Many reports have been made on transition metal complexes such as, for example, catalysts useful for organic synthesis reactions, e.g., asymmetric hydrogenation, asymmetric isomerization, asymmetric silylation, etc. Among them, many of the complexes in which an optically active tertiary phosphine compound is coordinated to a transition metal, e.g., rhodium, palladium, ruthenium, iridium, nickel, etc., exhibit excellent performance as catalysts for asymmetric synthesis reactions. To further improve the performance of these catalysts, various phosphine compounds having a special structure have hitherto been developed as disclosed, e.g. , in Chemical Society of Japan (ed. Kagaku Sosetsu, Vol. 32, pp. 237-238, "Yuki Kinzoku Sakutai no Kagakull" (1982). In particular, 2,2'-bis(diphenylphosphino 1,1'-binaphthyl (hereinafter abbreviated as BINAP) is one of the excellent phosphine ligands. Rhodium complexes and ruthenium complexes containing BINAP as a ligand have been reported in JP-A-55-61937 and JP-A-61-63690 (corresponding to U.S. Pat. No. 4,691,037 and European Patent 174,057), respectively (the term "JP-A" as used herein means an "unexamined published Japanese patent application"). Further, it has been reported that rhodium complexes and ruthenium complexes using 2,2'-bis[di(p-tolyl)phosphino]-1,1'-binaphthyl (hereinafter abbreviated as p-T-BINAP) as a ligand give satisfactory results in asymmetric hydrogenation and asymmetric isomerization as disclosed in JP-A-60-199898 (corresponding to U.S. Pat. No. 4,604,474 and European Patent 156,607) and JP-A-6163690, respectively. Furthermore, S. Inoue, et al. report in CHEMISTRY LETTERS, pp. 1007-1008 (1985) that asymmetric hydrogenation of nerol in the presence of, as a catalyst, a rhodium complex containing 2,2'-bis(dicyclohexylphosphino)1,1'-binaphthyl (hereinafter abbreviated as CYBINAP) gave citronellol having an optical purity of 66 %ee.
While a number of special phosphine compounds have been proposed in an attempt to provide complexes having improved performance as catalysts for asymmetric synthesis reactions as mentioned above, the conventional catalysts are still unsatisfactory in selectivity, conversion, and durability, depending on the type of the purposed reaction or reaction substrate. Hence, it has been demanded to develop a novel phosphine compound which provides a catalyst having markedly improved catalytic performance over the conventional ones.